Effect of Ketofol Versus Propofol as an Induction Agent on Ease of Laryngeal Mask Airway Insertion Conditions and Hemodynamic Stability in Pediatrics

An Observational Prospective Cohort Study

Bacha Aberra; Adugna Aregawi; Girmay Teklay; Hagos Tasew


BMC Anesthesiol. 2019;19(41) 

In This Article

Sampling Technique

From situational analysis mean of midyear population was used to get a total number of ophthalmic pediatric patients who underwent operation under general anesthesia using LMA in 2 months duration. The midyear population from the situational analysis was 960. So, the size of the population in 2 months was 960 divided by three gives us 320. The study participants were selected using a systematic sampling technique every two participants from daily operation schedule list until the required sample size was obtained. The first study participants were selected by lottery method. We spent two extra weeks to reach the number of propofol group is equal to ketofol group to get an equal sample size in both groups.

Intraoperative Procedure

After preoperative preparation, patients were shifted to the operation room, standard monitoring applied as routine. Baseline vitals were recorded and I.V. fluids were administered. Patients were preoxygenated with 6 L/min of Oxygen via a face mask, for 3 min and given injection atropine 0.02 mg/kg I.V. and fentanyl 1 μg/kg I. V prior to induction as the standard of care.

LMA insertion was performed 60 s after induction of anesthesia.[1] Following insertion, the position of LMA was assessed by observing movement of chest and reservoir bag through use of both spontaneous and assisted ventilation. After successful insertion of LMA, patients were allowed to breathe spontaneously. Assisted manual ventilation provided when the apnoea period is longer than 20 s from the time of LMA insertion to ensure that SpO2 remained above 95%. Manual ventilation was stopped when sufficient spontaneous respiration returned. Thereafter, anesthesia was maintained with isoflurane 2% and oxygen 100% with a flow rate of 3 L/min.

The patients were either induced with ketofol (0 .5mg/kg of ketamine plus 3 .0mg/kg of propofol) or 3 .5mg/kg or propofol alone. If the patients respond to stimulus after induction, further increments of propofol 0.5–1 mg/kg were given until loss of consciousness and loss of eyelash reflex in either technique. All patients who were exposed to either ketofol or propofol were compared to see different outcomes of both agents as an induction agent on ease of laryngeal mask airway insertion and hemodynamic stability. Insertion condition was graded by the same anesthetist who performs the procedure as.[9]

  1. Mouth opening: 1 – Full, 2 – Partial, 3 – Nil

  2. Coughing: 1 – Nil, 2 – slight, 3 – gross

  3. Swallowing: 1 – Nil, 2 – slight, 3 – gross

  4. Movement: 1 – Nil, 2 – slight, 3 – gross

  5. Laryngospasm: 1 – Nil, 2 – Mild, 3– Severe

  6. Ease of LMA insertion: 1-Easy, 2-Difficult, 3-Impossible

Mean blood pressure and heart rate were recorded one minute before induction (baseline), immediately after induction, immediately after LMA insertion, then at every minute for up to 3 min. The duration of apnoea was recorded via a digital timer as the time from the end of induction of anesthesia until the return of adequate spontaneous ventilation. Afterward, all patients who were scheduled for ophthalmic surgical operation under general anesthesia with LMA were enrolled in the study and assigned to either ketofol or propofol group randomly. Our study used those patients induced with propofol as a cohort group, where the same checklist was used to observe the case.

Data Collection Technique and Instrument

Data were collected using a pretested observational checklist. Data collectors were three bachelor degree holder anesthetist and they supervised by one master degree holder anesthetist. All anesthetists participating in the study including anesthetists who inserts the LMAs and administers the medications had at least 2 years of experience in conducting anesthesia.

Data Quality Assurance

Before recruiting patients into the study, training and orientation about the objective and process of data collection were provided by the principal investigator. To ensure the quality of data, a pre-test of the checklist was performed in Cure International Hospital before the actual data collection time. The completed checklist was submitted and reviewed on daily basis. Close supervision and daily information exchange were used as a means to correct problems during the course of data collection.

Consent for the survey was obtained from Addis Ababa University College of health sciences and confidentiality assured to improve the quality of data. Variables were checked by the expert before the actual data collection period for the purpose of consistency.

Statistical Methods

All data were analyzed by SPSS statistical package program (Version 20). Within the groups, the normality of variables was measured using the Shapiro-Wilk test. Differences of numerical data between groups were evaluated using student's t-test and Mann–Whitney U-test when appropriate. Categorical data were analyzed with the Chi-Square test. A pvalue of < 0.05 with the power of 80% was regarded as statistically significant.